Microsoft has reached an important milestone in the development of the new Office, as the Office engineering team on Thursday signed off on the Release to Manufacturing (RTM) build.

This milestone means the coding and testing phase of the project is complete and Microsoft is now focused on releasing the new Office via multiple distribution channels to its consumer and business customers.

Microsoft described the new Office as the most ambitious release of Office the company has ever done. It spans the full family of Office applications, servers and cloud services. The new Office has a touch friendly design that works on Windows 8 and unlocks modern scenarios in social, reading, note-taking, meetings and communications.

General availability is planned for the first quarter of 2013. Starting October 19, Microsoft's customers purchasing Office 2010 from local retailers or resellers will receive the new Office for free upon availability. Customers will also see a preview version of the new Office on Windows RT devices, beginning with the Windows 8 launch on October 26.

Additionally, Microsoft has a number of programs that provide its business customers with early access to the software. The company will begin rolling out new capabilities to Office 365 Enterprise customers in its next service update, starting in November through general availability. Microsoft's volume Licensing customers with Software Assurance will be able to download the Office 2013 applications as well as other Office products including SharePoint 2013, Lync 2013 and Exchange 2013 through the Volume Licensing Service Center by mid-November. These products will be available on the Volume Licensing price list on December 1. IT professionals and developers will be able to download the final version via their TechNet or MSDN subscriptions by mid-November.